The Museum of London Archaeology is recruiting a volunteer army of dog walkers, bird watchers, amateur historians and geology enthusiasts to help record sites that have been uncovered by storms and flood tides over the winter.

The project is being launched by the museum, with the help of a Heritage Lottery grant – an initial £1.4m, including a development grant of £75,000 – to help recruit the amateur archaeologists.

Artefacts including medieval bones and stone age cooking pots have been washed out of sites around the coast and unknown shipwrecks have been revealed.

The volunteers will be trained to help record information and use a web-based system to co-ordinate information on finds.

Every storm and flood tide of this long winter has washed archaeology out of thousands of sites around the British coastline. Medieval bones and stone age cooking pots have tumbled out of crumbling cliffs, Anglo-Saxon jetties have been scoured bare on the river Thames, and previously unknown shipwrecks have been revealed at sites including Dymchurch in Kent and Newquay in Cornwall.

Sites at rsk from rising sea levels, and from battering by waves and wind, include Roman forts and villas, prehistoric forests, and medieval port structures. Vulnerable sites include Meols on Merseyside, where traces of a port used centuries before the Romans took it over are endangered, Chichester Harbour, which contains the fragile traces of Iron Age saltworking sites, and the Roman port of Fishbourne.

At Lamorna Cove in Cornwall, part of the Grade II listed granite quay was ripped away by a storm last month. Further around the coast, a wooden boat was exposed in the sand at Newquay, thought to be a lifeboat from a steamer wrecked on the nearby rocks in a storm almost a century ago.

Taryn Nixon, the museum's chief executive, said: "We cannot halt the erosion or destruction of some of these sites but can ensure that the information about the remains is not lost. By creating a standardised, web-based recording system and providing training and new skills, we see this as an extraordinary opportunity for people across the country to create a lasting record that will benefit us all for years to come."

Nathalie Cohen, an archaeologist who will be working on the project, after years with the Thames Foreshore survey which also used amateurs and volunteers side by side with professionals, said: "The grant couldn't be more timely. This winter has really been shocking. There has been so much erosion happening in so many places, and accelerating where we were already aware of a problem, that it is really terrifying."

Particularly problematic sites, which oblivious tourists have been walking past as they disembark from ferries, are at Greenwich and the Tower of London, where remains of structures older than the tower itself are being eroded in the bank just above London Bridge. Further downstream, massive medieval jetty timbers are being damaged on every tide at Greenwich.

Cohen said reports from the public would be entered on a database which will gradually build, linking with older records and work by local history societies, to a record of thousands of sites, while professional archaeologists will be ready to intervene where there is a critical threat to a site of national importance.